Effect of female mouse urine on male mice

According to researchers at St. Mary's Medical School. Louis of Washington University, a group of steroids found in female mouse urine runs straight to the male mouse head. They found that these compounds activated nerve cells in the male mouse's nose unprecedentedly.

Dr. Timothy E. Holy, author of the article and professor of neurobiology and anatomy, said: 'These ketones, called glucocorticoids (GCCs), participate in energy metabolism. , function stress and resistance. They control many important aspects of the physiology of mice, which can theoretically bring any mouse to sniff them with a detailed view of the animal's health that makes them '.

Holy plans to continue further research to see if activation of male male nose nerves leads to certain behavioral responses. He investigated the male mouse's reaction to chemical signals from female mice to improve their understanding of the ability to recognize and learn in a much more complex human brain. In 2005, he discovered that female mice or their scent made male rats sing. He did not know whether the GCC steroids' effect on the male mouse nose helped promote this behavior.

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Science has long recognized that urine, sweat and other body fluids contain chemical communication signals called hormones that can affect the physiology or behavior of other animals. Most mammals use the information of these signals for social purposes, such as setting boundaries or dominant positions, as well as flirting and couples. However, in many cases, the specific chemical composition of these signals is unknown.

The new study, published in The Journal of Neuroscience, is directed by graduate student Francesco Nodari, who recognizes compounds that act as a powerful hormone for the mouse nose. These hormones activate nerve cells 30 times more frequently than the previously identified hormones in female mouse urine combined. In addition, some new signals activate specific nerve cells. This may mean that the rat brain has the ability to assess different aspects of female mouse health by selectively analyzing individual pheromones.

Stress in female mice tripled their GCCs in their urine, which is directly related to female mouse's health and GCC hormones.

GCC hormones that Nodari identifies are sulfated, meaning they have a chemical group that includes sulfur and oxygen atoms. This group is added to inactivate steroids before being released to the urine. When Nodari used enzymes to extract these groups, GCC lost its ability to activate the nerve. This shows that the harmonious relationship between GCC sulfate and nerve cells is the result of evolution to transmit information from female mice to male mice.

The nerves in the mouse nose are located in a region called the accessory olfactory system. Humans and monkeys and their families do not have this system, but they still exist in most mammals and some reptiles. This system, found in a structure called vomeronasal organ, provides information for another part of the brain, not the main olfactory system. Like the main olfactory system, it specializes in detecting airborne particles. But researchers believe that the accessory olfactory system focuses on compounds from very close sources or touching animals.

According to Holy, the focus on odor from nearby positions makes the accessory olfactory system 'both a taste system and a sense of smell' . He suggested that GCC hormones account for about 75% of the signals in mouse urine that the male olfactory system found in male mice.

He said: 'Because these hormones are very good at activating the accessory olfactory system, they will be very helpful in understanding the function of this system. High levels of activation also mean that they have a lot of potential to promote hormonal research. '